Vaccination is one of the most effective tools for mitigating the impact of influenza epidemics and pandemics. However, commercially available flu vaccines are in general directed specifically towards a specific strain contained in the vaccine. Current flu vaccine strategies have typically demonstrated a lack of cross-protective immunity (i.e., the vaccine is not effective against multiple strains or types of flu virus). For example, authorities from many countries collaborate with one another to predict the strain of influenza A virus that is likely to cause flu in the upcoming months. While these types of vaccination programs can work to contain a seasonal flu, they become less effective when the flu epidemic is caused by a different influenza A strain than was predicted. In addition, there is often a lack of long-term effectiveness (i.e., the vaccine protection is short lived and not sufficiently potent).